Eleoteic aeo lamp



(No Model.)

RI H. JAHR. 5

ELECTRIC ARG LAMP. Y v

No; 545,594. Patented Sept. 3,1895.

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. RuDoLE I-IQJAHR, on orLADEN, GERMANY.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 545,694, dated September 3, 1895. Application filed November 26,1894. serai No. 529,953. or@ modas Patented in Bugnm'sepamter 10,1894, u0.111,772.

To all whom it may concern:

Be it known that I, RUDOLF HERMANN JAHR, a subject of the King of Prussia, German Emperor, residing at Opladen, in the Kingdom of Prussia, German Empire, have invented a new and useful-Electric-Arc Lamp, (for which'l have obtained apatent in Belgium, No.1l1,772,bearing date September 10, 1894,) of which the following is'a specification.

This invention relates to electric-arc lamps, and has for its object to allow the brilliancy of the lamp or its current intensity to bevaried according to special requirement and to cause the lamp to work with such length of arc or current tension as is most favorable for the special degree of brilliancy it is desired to burn with.

To this end the present invention consists in combining the regulating-helix of the lamp with means adapted to vary the action of said helix according to requirement and to simultaneously adjust the main regulating resistance of the lamp in accordance with said variation. The said means 'substantially consist in an auxiliary resistance determining the current ilow through the regulating-helix and a connection between this auxiliary resistance and the main regulating resistance of the lamp, whereby both these resistances are caused to move in conformity with the current intensity and current tension necessary for the degree of brilliancy desired.,

The present invention is applicable whether the regulating-helix is in the main or light circuit of the lamp or in a derivation of, or shunt to this circuit. In the first case the said auxiliary resistance or graduator, as it may be called, is so arranged as to form a shunt to the main-current helix, while'in the second case it is placed in or forms part of the regulating-shunt. The first-named arrangement is that for main-current lamps proper or lamps regulated by means of a helix traversed by the main or light current, and the secondnamed one that for shunt-lamps proper or lamps the regulation of which is effected by a helix placed in a derivation branched off from the terminals of the lamp, while both the said arrangements are serviceable for differential lamps or lamps regulated by means of any difference taking place between the action of two helices, one placed in the main or light circuit of the lamp (main or prime helix) and the other in a shunt to the arc (shunt or differential helix.)

As my invention will best be understood by contemplating its combination with a differential lamp and the 4latter simultaneously permits both forms of application to be made use of, I proceed to' more particularly describe it on the base of a differential lamp.

(a.) Varying the current "intensity b i/ naryt'ng the action of the mata helix or that through which circulates the main or h'ght current- The lamp is in equilibriumthat is to say, it will burn when the number of ampere-windings of the main helix is equal to that of the differential helix (differential lamps) or when the magnetic force created by a main helix having a given number of ampere-windings is equal to the given force of a spring (maincurrentlamps and shunt-lamps). In a differential lamp the number of ampere-windings maintaining the equilibrium may easily be determined on the prime helix, as is well known. For instance, when the said helix comprises eighty-six windings and the lamp burns quietly on being fed with a current of ten ampres, then the number of ampre-windings on either helix will be eight hundred and sixty, the thickness of the wire composing the prime helix being one millimeter, or, in other terms,

the prime helix opposing a resistance of 0.937. Supposing such a lamp, and supposing, further, the same be fed with a current intensity of two ampres, then the number of windings of its prime helix will be reduced to 8 O--z/lO, and it will burn provided its co-operating counter-force be caused to be balanced bythe said reduced number of ampere-windings. Moreover, this lamp will also burn with a current intensity of ten ampres when a shunt is arranged tothe main or prime helix and provided with such a resistance as to allow eight ampres to be diverted from the said helix, so that the number of ampres received by the latter is but two ampres. As

long as the current flowing through the arc has an intensity of ten ampres, the lamp will continue to'burn quietly. When the said inteusity is caused to fall below ten ampresfor instance, to nine ampres-the shunt will IOO not be altered, but continue to divert eight ampres from the main helix. Consequently the latter will be fed with one ampre only instead of with two ampres, and its number of ampere-windings proportional-ly reduced, so that it discontinuos to balance its counteri'orce. This state ot the lamp will be maintained until by the action of the said counterforce two ampres are again permitted to flow through the main helix. From this it results that, when the lamp is desired to burn with a two-ampres brilliancy, the said resistance must be raised to an infinitely great amount or the second shunt cutout totally.

From the foregoing it is readily to be conceived how the lamp can. be enabled to burn with any number of ampres between two and ten ampres as the minimum and maximum intensities of current or the minimum and maximum degrees of brilliancy, it being only necessary to arrange a shunt to the main helix and to provide this shunt with a resistance capable of being so adjusted as to allow but two ampres to pass through the main helix, whatever number of ampres is admitted to the lamp, provided this number be within the limits oi' two and ten ampres. For instance, when the lamp is desired to develop a brilliancy corresponding to live ampres, then the auxiliary resistance or graduator has to be so adjusted as to cause three ampres to be diverted from the prime helix.

The principle disclosed by the foregoing may be expressed as follows: In order to rcduce the brilliancy of the lamp or its current intensity, the action of its main helix must be increased by increasing the resistance of the shunt to said helix. Moreover, in order 'that in all instances the lamp may burn with a current tension best adapted for the degree of brilliancy desired, the main regulating resistance of the lamp has to be varied simultaneously with the variation of the auxiliary resistance, so that the current intensity acts with such tension as experience has proved to be best.

The variations of the auxiliary and main regulating resistances are found by methods of calculation known to electricians.

The following is a table indicating several amounts of auxiliary resistance and current tension for lamps intended to burn with any intensity within the limits of two and ten ampres:

Intended bril Maiuhclix Difference Tension, the shunt.

volts.

Itis well understood that instead of arrang provide for as many shunts as variations of brilliancy are desired and to provide each individual shunt with the special resistance required for the degree of brilliancy to be obtained by the respective shunt.

Vary/'ing 'the current intensity by 'varyt'ng the action of the dcreutiul LeZz':c.-I `rom case a., where the action ot' the main helix has to be increased by increasing the resistance of the shunt to the main helix, in order to permit the current intensity to be reduced, and from the contemplation that a maximum of current intensityis caused to tlow through the arc when the differential shuutmi. e., the shunt to the arc-exerts its maximum oi' action, it results that the current intensity can also be reduced by increasi ng the resistance in the differential shunt. Thus to enable the lamp to burn at different times with ditl'erent degrees of brilliancy the diiterential shunt of same has to be provided with an adjustable auxiliary resistance or graduator and the latter adjusted to allow such a number ot' ampres to pass as corresponds with the degree ot brilliancy desired, it being well understood that. the main regulatingresistance must simultaneously be varied, as already stated.

The amount oi' variation of both the auxiliary and the main regulating resistance is found by methods of calculation known to electricians.

On the annexed sheet of drawings, Figure l is a diagram of a differential lamp with the auxiliary resistance or graduator placed in a shunt to the prime helix, and Fig. 2 a dagram of a differential lamp with the graduator placed in the circuit of the dilerential helix.

In both iigures similar letters of reference are employed for indicating identical parts.

In Fig. l, o is the upper carbon,fatl1e lower carbon, L L the main circuit of the lamp, and H the helix placed in the same, or the prime helix. S is the shunt to the arc, and N the helix arranged in the same, or the diiterential helix. Il R is the usual regulating resistance ot the lamp. The light current ilows from the positive pole of the source ot' electricity, through the main L and the regulating resistance lill, tothe upper carbon, from this to the lower carbon, whence it passes back to the negative pole of the source of electricity through the prime helix H and the main L. .as seen, a shunt h 71. isarranged to the prime helix il, and in this shunt is placed a resistance N R, which is adjustable. This auxiliary resistance N R is what I call the graduates It this shunt is switched out the whole light current will be caused to pass through the windings ofthe prime helix; but when it is switched in but such fraction of the current will be allowed to pass through the prime helix as corresponds to the amount ol resistance opposed by the graduator N R. rJlhe two resistances N It and Il R are so connected by appropriate means-tor instance, by a hand pivotcd ICO IIO

in its center and the middle portion of which is made of non-conducting material, while its end portions h and h2 are conductors-that any variation of one of them causes such variation of the other as is best suited for the degree of brilliancy obtained by that variation.

In Fig. 2 the adjustable auxiliary resistance or graduator is placed in the circuit S of the differential helix N, while there is no shunt to the prime helix H. As long as the graduator is switched out the full amount f differential current will pass through helix N and the lamp will burn with its maximum degree of brilliancy; but when it is switched in only such an amount of current will be allowed to circulatethrough the differential helix as corresponds to the amount of active resistance of the graduator and the lamp will burn with a correspondingly lower degree of brilliancy. In this case, also, a connection has to be established between the two resistances I-I R and N R, as described with reference to Fig. l, this connection being omitted from the drawings. It is obvious that the graduator may also be placed in the circuit of the prime helix or in a shunt to the differential helix, and that in such case the effect will be the reversal of that described with reference to cases a and b, respectively.

What I claim is- 1. In electric arc lamps the combination, with the upper and lower carbons, the regulating helix, and the main regulating resistance ot' the lamp, of an auxiliary resistance for changing the action of the said helix, and a connection between the said auxiliary resistance and the main regulating resistance, substantially as and for the purpose described.

2. In electric arc lamps the combination, with the upper and lower carbons, the regulating helix, and the main regulating resistance of the lamp, of an adjustable auxiliary resistance for changing the action of the said helix, and a connection between the said auxiliary resistance and the main regulating resistance, substantially as and for the purpose described.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

RUDOLF H. JAHR.

Witnesses:

FRITZ SoHRoDER, MARIA NAGEL. 

